That means, we only want to use server3.maxsource.net as our cPanel/WHM certificate, and all the mail services will use mail.maxsouce.net as the certificate.

However, when I set my Thunderbird, incoming server(POP3) as mail.maxsource.net and outgoing server(SMTP) as mail.maxsource.net, I got some problem with sending emails. I always get a warning says I have attempted to establish a connection with mail.maxsource.net, but the certificate belongs to server3.maxsource.net.